Metal deactivators



Patented Dec. 12, 1950 METAL DEACTIVATORS Joseph A. Chenicek, Riverside,111., assignor to Universal Oil Products Company, Chicago, 11]., acorporation of Delaware No Drawing. Application October 27, 1947, SerialNo. 182,463

4 Claims.

The present invention relates to a method of stabilizing organiccompounds, and particularly to the stabilization of organic substancesagainst deterioration by oxygen catalgzedin the presence of or bycontact with certain oxidation promoters. plicable to preventing suchdeterioration of edible fats and oils, foods, monomers, resins, rubber,etc., it is particularly applicable to the stabilization ofolefin-containing hydrocarbon distillates, such as cracked or polymergasolines.

One method of refining gasoline is the copper sweetening process, inwhich process the gasoline is contacted with a copper-containingreagent. As a result of this treatment, the sweetened gasoline usuallycontains relatively small amounts of copper compounds which have acatalytic effect on oxidation reactions occurring when the gasolinecomes in contact with air. In addition, gasolines come in contact withvarious metals in the course of refining, storing and shippingoperations, and the metal may catalyze the oxidation reactions. In somecases, this may also re- .sult in the gasoline containing minor amountsof such metals as copper, iron, cobalt, nickel, chromium, lead, etc.,which have a detrimental effect on the stability of the gasoline.

In one embodiment the present invention relates to a method ofstabilizing an organic substance subject to oxidative deterioration,which comprises adding thereto a metal deactivator prepared bycondensing 2 mols of ammonia with at least 2 mols of an ortho-hydroxyaromatic aldehyde.

In a specific embodiment the present invention relates to a method ofstabilizing cracked gasoline containing copper, which comprises addingthereto hydrosalicylamide in an amount sufficient to suppress thecatalytic effect of said copper.

The novel metalwdeactivator of the present invention may be representedby the following general formula:

where R. is selected from the group consisting of hydrocarbon, hydroxyhydrocarbon, alkoxy hydrocarbon and alkoxyhydroxy hydrocarbon radicals,and R is selected from the group consisting of hydrogen, alkyl andalkoxy radicals.

It is readily apparent that the present invention contemplates anextensive number ofcompounds which may be prepared and used within thebroad scope of the present invention. It is While the present inventionis apunderstood that, while all of these compounds will have somepotency as metal deactivators, they are not necessarily equivalent andthat the choice as to the particular metal deactivator to be used in anygiven instance will depend upon the particular organic material to betreated.

Typical examples of the metal deactivators of the present invention areillustrated by the following specific compounds.

Where R in the above formula is a hydrocarbon group, it may comprise anaryl, alkaryl, alkyl, arall-gyl or cycloalkyl group. Where R is an arylgroup, the metal deactivator will comprise phenyl-bis-(salicylalamino)-methane, naphthylbis-(salicylalamino) -methane, etc. Where R comprisesan alkyaryl group, the metal deactivator will comprise such compounds asa methylphenyl bis (salicylalamino) methane, ethylphenyl bis(salicylalamino methane, propylphenyl bis (salicylalamino) methane,butylphenyl bis (salicylalamino) methane,amylphenyl-bis-(salicylalamino)-methane, etc. It is understood that thealkyl group may be in either the ortho, metal or para position, and alsothat the aryl group may contain 2 or more alkyl radicals attachedthereto.

Where R comprises an alkyl radical the metal deactivator will includesuch compounds as 1,1- bis- (salicylalamino) -ethane, 1,1-bis-(salicylalamino) propane, 1,l-bis-(salicylalamino) -butane,1,1-bis-(salicylalamino) -pentane, 1,1-bis- (salicylalamino) hexane,'1,1bis (salicylalamino) heptane, 1,1 bis (salicylalamino)- octane, etc.Where R comprises an aralkyl group, the metal deactivator will includesuch compounds as 1,1 bis (salicylalamino) 2 phenyl ethane,1,1-bis-(salicylalamino) -3-phenyl propane, 1,1-bis-(salicylalamino)-4-phenyl butane, etc.

Where R in the above formula comprises a cycloalkyl group, the metaldeactivator will be cyclohexyl-bis-(salicylalamino) -methane which mayor may not contain alkyl, hydroxy and/or alkoxy groups attached to thecyclohexyl ring.

It will be noted that the above compounds comprise the class in which Rof the above general formula is hydrogen. Compounds in which R in theabove formula comprises a hydroxy hydrocarbon are preferred metaldeactivators. This class of metal deactivators are represented byhydrosalicylamide which may otherwise be named (2 hydroxyphenyl) bis(salicylalamino) methane. Preferred metal deactivators also includecompounds in which the R radical comprises a alkoxyhydroxy oralkylhydroxy aryl methane,

group, the latter being included within the broad class of hydroxyhydrocarbon substituents. Pre ferred metal deactivators of thealkoxyhydroxy hydrocarbon class include(2-hydroxy-3-methoxyphenyD-bis-(Z hydroxy-3-methoxybenzalamino)-methane,- (Z-hydroxy-S-ethoxy-phenyl) bis (2 hydroxy I 3ethcxybenzalamino) methane, (2-hydroxy-3-propoxyphenyl) -bis-(2- hydroxy3 propoxybenzalamino) methane, etc. It will be noted that the threephenyl rings all contain similar substituent groups in the samepositions. This is generally preferred because of ease of manufacture aswill be hereinafter described in further detail. It will also be notedthat in these compounds, the R groups represent alkoxy radicals.

Where R in the above general formula comprises an alkylhydroxy radical,the metal deactivator will include such compounds as(Z-hydroxymethylphenyl) bis (2 hydroxy 5 methyl-benzalaminobmethane,(2-hydroxy-5-ethylphenyl) bis (2 hydroxy 5'- ethyl benzalamino)-methane, (Z-hydroxy-B-propylphenyl) bis (2 hydroxy 5 propylbenzalamino)- methane, (2-hydroxy-5-tert-butyl-phenyl) -bis-(2-hydroxy-5-tert butyl-benzalamino) -methane, (2 hydroxy 5 4 amylphenyl) bis (2 hydroxy-5-amyl-benzalamino)-methane, etc. It isunderstood that the akyl radicals may be attached to different positionson the aryl rings and also that two or more alkyl groups may be attachedto the aryl rings. It will be noted that these metal deactivatorscomprise compounds in which the R groups are alkyl radicals.

Where R in the above general formula comprises an alkoxy hydrocarbongroup. the metal deactivators will include such compounds as (2methoxyphenyl) bis (salicylalamino)- '(2 ethoxyphenyl) bis(salicylalamino) -methane, (Z-propoxyphe'nyl) -bis- (salicylalamino)-methane, etc. It is understood that these compounds may contain alkylgroups attached to the ringin addition to the alkoxy groups. It will benoted that these metal deactivators comprise compounds in which the Rgroups in the above general formula are hydrogen radicals.

Metal deactivators of the present invention are readily prepared by thecondensation of 2 mols of ammonia with 3 mols of aldehydes of which atleast 2 mols are an ortho-hydroxy aromatic aldehyde. As hereinbefore setforth, preferred metal deactivators comprise those in which the B. groupis a substituted phenyl group having the same substituents as thearomatic aldehyde originally used to prepare the metal deactivator. Thissimplifies preparation of the metal deactivator, which then is readilyprepared by the condensation of 2 mols of ammonia with 3 mols of thedesired ortho-hydroxy aromatic aldehyde. Thus,

hydrosalicylamide is readily prepared by adding concentrated ammoniumhydroxide to an alcoholic solution of salicylaldehyde and, after thereaction has gone to completion, the water formed in the reaction isremoved and the final product is recovered in any suitable manner. Othermetal deactivators in which the 3 phenyl rings contain hydroxy and alkylor alkoxy radicals are similarly prepared by the condensation of 2 molsof ammonia with 3 mols of the desired substituted aromatic aldehyde.Thus, for example, 3 mols of ortho-vanillin may be condensed with 2 molsof ammonia. When the R group is diflerent than the other phenyl rings,the desired reactants are mixed in the proper proportions to form thedesired metal deactivator as, for example, the condensation of 2 mols ofammonia with 2 mols of salicylaldehyde and 1 mol of orthovanillin.

In general, it is preferred that the total number of carbon atoms in themetal deactivator be not greater than about 30, as it has been foundthat, within certain limits,.the potency of the deactivator decreaseswith inclusion of hydrocarbon radicals of high molecular weight.

The metal deactlvators of the present invention are generally utilizedin addition to gum inhibitors. The function of the metal deactivator isentirely distinct from the function of the gum inhibitor. For example,the gum inhibitor does not suppress the catalytic action of the metal toany considerable extent and, on the other hand, the metal deactivatordoes not suppress gum formation per se to any considerable extent, butserves only to deactivate the metal compounds and thereby destroy thecatalytic effect thereof to enhance oxidative reactions.

Any table gum inhibitor may be employed along wi h the metal deactivatorof the present invention. These gum inhibitors are well known andgenerally include various phenols, amines, amino phenols, as well asfractions of wood tar oil, etc. Some of these inhibitors are marketed inthe form of a solution in a suitable solvent such as alcohol, ether,etc. A particularly suitable gum inhibitor comprisesN-N'-di-seccndarybutyl-p-phenylene dlamine. larly suitable gum inhibitorcomprises a mixture of a major proportion of N-n-butyl-p-aminophenol anda minor proportion of N-N'-di-nbutyl-p-phenylene diamine in an alcoholicsolvent.

The gum inhibitors are usually added to gasoline in concentrations offrom about 0.001% to about 0.1% by weight and the metal deactivator isgenerally added to gasoline in a smaller concentration which may rangefrom about 0.0005% c able solvent which is not reactive therewith. In

some cases, when a solvent is used for the gum inhibitor, the samesolvent may be used for the metal deactivator and thus the gum inhibitorand metal deactivator, when desired, may be prepared as a mixture in asuitable solvent and the combined inhibitor and deactivator marketed asa single commodity of a. two-fold purpose.

The following examples are introduced to further illustrate the noveltyand utility of the pre ent invention but not with the intention ofunduly limiting the same.

The metal deactivators of the present invention were preparedby thecondensation of the reactants as shown in the following table. Thesemetal deactivators were tested in a Pennsylvania cracked gasoline, andthe results are reported as the induction period in minutes. Theinduction period is determined by the oxygen bomb stability test whichis the standard method of evaluating the storage stability of gasoline.

The Pennsylvania cracked gasoline used in these tests had an inductionperiod of minutes. Upon the addition of 0.005% by weight of a guminhibitor comprising N-N'-di-secondary butyl-p-phenylene diamine, theinduction period was increased to 470 minutes. To show the deleteriouseffect of metal, copper in the form of copper oleate was added in anamount of 1 milligram of copper per liter of gasoline to differentsamples of the gasoline containing gum inhibitor.

Another particuasaaaos riod was increased as shown in the followingtable:

Table Compound Resctants M. P g gfg C. Minutes hydromlicylamido.salicylaldehyde, sm- 165-6 485 moms.(z-hydroxy-s-methfi-hydrorx-s-methoxy- 148-149 48) oxypbenyD-bis-(il'benral ehyde, amhydroxy-a-metho mania. bensslamino methane.(2-hYdroxy-6-tcrtbu- 2-hydroxy-frtertbu- 86-87 48) y HhcnyD'biI-(I-tylbensaldehyde, by roxy-li-tertammonia. but lino)-(fl-hydroxy-lS-methyl fl-hydroxy-o-methyl- 74-76 470henyl)-bis-(2-hybenralde yds, amrcxy-ii-meth l mania. j bensalamlnoyllbis-(salicyn-bnt dehyde (l 7749 310 lahmimD-butsne. moisallcylaldehyde, (2 mols), amllhl 1| heptsl t i e hydefl 1) 711:; am

, sas cymo lslamino)-heptanc. mlicylaldchyde (2 mols ammonia.phsnyl-hb-(mlicylalabans-aldehyde (1 mol), 116-117 265 Imam-methane.@licglsldehydc (2 mols ammonia.

1 Metal deactivator added in an amount of 0.001% by weight.

whereBigselectediromthegz-oup of hydrocarbon.

consisting hydroxyhydrocarbomalkmhyi 8 drocarbon and alkoxyhydroxyhydrocarbon radicals. and R. is selected from the group consisting ofhydrogen, alhl and alkoxy radicals.

2. Gasoline containing unsaturated hydrocarbons which tend to form gumsand a metal compound which normally catalyzes oxidatlve deteriorationand additionally containing a small amount of a metal deactlvator havingthe general formula II R H R OH H O R where R is selected from the groupconsisting of hydrocarbon, hydroxy hydrocarbon, alkoxy hydrocarbon andalkoxyhydroxy hydrocarbon radicals, and R is selected from the groupconsisting of hydrogen. alkyl and alkoiw radicals.

3. Cracked gasoline containing a small amount of a gum inhibitor toprevent gum formation and a smaller amount of a metal deactivator havingthe general formula I! R H R OH I H0 R where R is selected from thegroup consisting of mula n a n n on no a' where R. is selected from thegroup consisting of hydrocarbon. hydroxy hydrocarbon. alkon hydrocarbonand alkoxyhydroxy hydrocarbon radicals, and R is selected from the groupconsisting of hydrogen. alkyl and alkoxy radicals.

JOSEPH A. CHENICIK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS 7 Number Name Date 2,181,122 Downing et al. Nov.28, 1939 2,284.28! Downing et al. In! 36. an

2. GASOLINE CONTAINING UNSATURATED HYDROCARBONS WHICH TEND TO FORM GUMSAND A METAL COMPOUND WHICH NORMALLY CATALYZES OXIDATIVE DETERIORATIONAND ADDITONALLY CONTAINING A SMALL AMOUNT OF A METAL DEACTIVATOR HAVINGTHE GENERAL FORMUAL